1. Field of the Invention
The present invention relates to an image input apparatus for reading an image for example on a photographic film by transmissive illumination and converting said image into electrical signals.
2. Related Background Art
A conventional image input apparatus of the above-explained kind is configurated as shown in FIGS. 14 and 15 and as will be explained in the following.
The apparatus is divided into a front part 201 and a rear part 202, with a recessed part 203 in the middle.
Said recessed part 203 is provided to accommodate a film holder 205, which is mounted on a stage 204 fixed to the front part 201.
The rear part 202 houses therein a lamp for illuminating a film set in the film holder 205, an illuminating lens, various circuits and a power supply unit.
Also the front part 201 houses therein a mechanism for moving the stage 204, a projection lens and a line sensor.
The light from the lamp in said rear part 202 is transmitted by the illuminating lens 206 and illuminates the film set in the film holder 205. The light transmitted by said film enters the projection lens in the front part 201, and is focused on the line sensor. A horizontal movement of the stage 204 causes the film to move likewise, and the entire image on the film is scanned in succession and focused on the line sensor.
In this operation, in order to exclude the external light, a cover 207 is moved in a sliding movement to cover the recessed part 203 as shown in FIG. 15.
The image focused on the line sensor is converted into electrical signals which are subjected to amplification and correction.
The above-explained prior art has been associated with following drawbacks.
The apparatus is difficult to make compact and involves limitation in the design, as the recessed part 203 required for mounting the film holder 205 occupies a considerable space.
Also the mounting of the film holder 205 onto the stage 204 is difficult since it is positioned vertically in the recessed part 203.
Furthermore, as the recessed part 203 needs to be covered by the cover 207 for avoiding the intrusion of external light, the number of component parts increases inevitably.